may well be, in Breconshire (now the bottom bit of Powys), longbarrows and round barrows are the rarity, more often than not it's long cairns and round cairns made from piles of stone.
There are a fair few cairns around the moors.... n' possible cairn circles. The Woofa Bank enclosure is quite a wide arc of bronze age walling, with rock art in and around it. There are a fair few settlement and field walls around the moor, but Woofa Bank seems different in some way, with a standing stone and rock art in the middle of it.